In recent years, a multi-core CPU is developed. The more the cores is, the better efficiency of the CPU is. However, the price of the CPU is higher.
For example, a dual-core CPU, a three-core CPU and a quad-core CPU which are usually manufactured by the same semiconducting process. In other words, four cores are manufactured in a single chip at the same time. The number of the CPU cores is determined according to the operation condition in the testing procedure after manufactured.
For example, in the testing procedure, all the four cores operate normally; the CPU is indicated to be a quad-core CPU. In a similar way, when one of the four cores cannot operate stably, this core is locked, and the CPU is indicated to be a three-core CPU. When two cores cannot operate stably, the two cores are locked and the CPU is indicated to be a duel-core CPU.
FIG. 1 is a schematic diagram showing the connection between components of a conventional computer system. In the computer system 100, a north bridge chip 120 is connected between a CPU 110 and a south bridge chip 130. The south bridge chip 130 is further connected with a basic input output system (BIOS) 150. Currently, the CPU 110 supplied by the AMD Company has an advanced clock calibration (ACC) function to unlock the locked cores to enhance the work efficiency.
When the ACC function is executed, the south bridge chip 130 operates according to the setting and the control of the BIOS 150, and thus the south bridge chip 130 regulates the duty cycle of the clock signal of the CPU 110 directly and completes the ACC function to enhance the efficiency of the CPU 110. Moreover, when the ACC function is completed, the core unlocking function of the CPU 110 is completed. Since the cores of the CPU 110 increase, the operating rate and the operating stability is promoted greatly.
However, in order to achieve the core unlocking function of the CPU 110, the computer system manufacturer has to buy the same series of the north bridge chip 120 and the south bridge chip 130 manufactured by the same company and dispose them on the computer system 100. There are no other methods for unlocking the cores of the CPU 110 except the above method. Since the computer system manufacture should buy the same series of the north bridge chip 120 and the south bridge chip 130, the cost increases.